U.S. patent application number 12/597297 was filed with the patent office on 2010-08-12 for energy storage assembly with poka-yoke connections.
Invention is credited to Kiyoko Abe, Peter Birke, Frank Czogalla, Michael Keller, Kazunori Ozawa, Kazuhiro Takahashi, Swen Wiethoff, Hideo Yabe.
Application Number | 20100200314 12/597297 |
Document ID | / |
Family ID | 39671907 |
Filed Date | 2010-08-12 |
United States Patent
Application |
20100200314 |
Kind Code |
A1 |
Birke; Peter ; et
al. |
August 12, 2010 |
ENERGY STORAGE ASSEMBLY WITH POKA-YOKE CONNECTIONS
Abstract
An energy storage assembly with a plurality of flat
electrochemical cells, each of them includes a pair of electrodes
which electrically connect the electrochemical cells with each
other through outward electrode terminals, wherein each
electrochemical cell includes as a pair of outward electrode
terminals a straight outward terminal and a curved outward
terminal, the electrochemical cells are connected with each other
that a straight outward terminal of one of the electrochemical cell
is connected with a curved outward terminal of an adjacent
electrochemical cell.
Inventors: |
Birke; Peter;
(Glienicke/Nordbahn, DE) ; Wiethoff; Swen;
(Berlin, DE) ; Keller; Michael; (Baden Baden,
DE) ; Czogalla; Frank; (Berlin, DE) ;
Takahashi; Kazuhiro; (Yamagata-Prefecture, JP) ;
Yabe; Hideo; (Saitama-Prefecture, JP) ; Abe;
Kiyoko; (Yamagata-Prefecture, JP) ; Ozawa;
Kazunori; (Miyagi-Prefecture, JP) |
Correspondence
Address: |
RATNERPRESTIA
P.O. BOX 980
VALLEY FORGE
PA
19482
US
|
Family ID: |
39671907 |
Appl. No.: |
12/597297 |
Filed: |
April 23, 2008 |
PCT Filed: |
April 23, 2008 |
PCT NO: |
PCT/EP08/03262 |
371 Date: |
April 16, 2010 |
Current U.S.
Class: |
180/65.21 ;
429/158; 903/907 |
Current CPC
Class: |
H01M 8/0247 20130101;
H01M 8/2465 20130101; H01M 50/54 20210101; Y02E 60/50 20130101;
Y02E 60/10 20130101 |
Class at
Publication: |
180/65.21 ;
429/158; 903/907 |
International
Class: |
B60K 6/28 20071001
B60K006/28; H01M 2/26 20060101 H01M002/26; H01M 6/46 20060101
H01M006/46 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2007 |
DE |
10 2007 019 625.5 |
Claims
1.-20. (canceled)
21. Energy storage assembly with a plurality of flat
electrochemical cells, each of the flat electrochemical cells
comprising a pair of electrodes which electrically connect the
electrochemical cells with each other through outward terminals,
wherein each electrochemical cell comprises a pair of outward
terminals, a straight outward terminal and a curved outward
terminal, wherein the electrochemical cells are connected with each
other such that a straight outward terminal of one of the
electrochemical cells is connected with a curved outward terminal
of an adjacent electrochemical cell.
22. Energy storage assembly according to claim 21, wherein each
outward terminal comprises at least one bulge.
23. Energy storage assembly according to claim 21, wherein each
outward terminal comprises at least two bulges, which are
horizontally separated by a vertical slot in the outward
terminal.
24. Energy storage assembly according to claim 21, wherein each
outward terminal is outwardly slotted in two tags.
25. Energy storage assembly according to claim 24, wherein one
bulge is arranged on each tag of an outward terminal.
26. Energy storage assembly according to claim 21, wherein the
outward terminals of each electrochemical cell are arranged on
opposite ends of one cell side of their electrochemical cell.
27. Energy storage assembly according to claim 21, wherein the
outward terminals of each electrochemical cell are arranged on one
end of one cell side of their electrochemical cell.
28. Energy storage assembly according to claim 21, wherein each
outward terminal has a thickness of at least 1 millimeter.
29. Energy storage assembly according to claim 21, wherein each
outward terminal is composed of at least copper.
30. Energy storage assembly according to claim 21, wherein each
outward terminal is composed of at least copper coated with a
protection layer.
31. Energy storage assembly according to claim 30, wherein the
protection layer is composed of stannous or nickel or an alloy.
32. Energy storage assembly according to claim 30, wherein the
alloy is an alloy of aluminum manganese or aluminum copper.
33. Energy storage assembly according to claim 21, wherein the
outward terminals of each electrochemical cell are connected with
an inner part of their electrochemical cell through coupling
elements.
34. Energy storage assembly according to claim 33, wherein the
coupling elements are rivets, crimps, bolts or weld points
integrated in the inner part of the cell.
35. Energy storage assembly according to claim 21, wherein a
predetermined number of electrochemical cells are arranged in at
least two or more modules.
36. Energy storage assembly according to claim 35, wherein the
modules are separated by a protection element.
37. Energy storage assembly according to claim 21, wherein the
electrochemical cells are connected in series.
38. Energy storage assembly according to claim 21, wherein the
electrochemical cells are connected in parallel.
39. Energy storage assembly according to claim 21, wherein the
electrochemical cells are connected in parallel-series.
40. An electric car having a driving motor driven by power supplied
from the energy storage assembly according to claim 21.
41. A hybrid type electric car having a driving motor and an
internal combustion engine, wherein the driving motor is driven by
power supplied from the energy storage assembly according to claim
21.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the U.S. national phase application of
PCT/EP2008/003262, filed Apr. 23, 2008, which claims priority from
German application serial No. 10 2007 019 625.5, filed on Apr. 24,
2007, the content of such applications being incorporated by
reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to an energy storage assembly
and an electric car or a hybrid type electric car using the same.
The energy storage assembly (also called battery pack) comprises a
plurality of flat electrochemical cells (also called battery cells)
each of them comprises a pair of electrodes which electrically
connect the electrochemical cells with each other through outward
terminals.
BACKGROUND OF THE INVENTION
[0003] In order to satisfy requirements such as higher input-output
power sources for applications, e.g. electric cars, hybrid cars,
electric tools, etc. new energy storage assemblies, e.g. lead-acid
batteries, lithium-ion batteries, nickel metal hydride batteries,
nickel-cadmium batteries and electric double layer capacitors, etc.
have been developed.
[0004] These new energy storage assemblies power the electric
driving motor and the vehicle on-board electrical system. To
control the charge-discharge procedures of the energy storage
assembly a controller is integrated which manages the
charge-discharge procedures, the conversion from braking energy
into electric energy (=renewable braking), etc, so that the energy
storage assembly can charge during vehicle operation.
[0005] The energy storage assembly or each single electrochemical
cell should exhibit good characteristics such as a maximum voltage
range of 100 V to 450 V with current of 400 A and for extreme
condition, e.g. high temperature, with current up to 500 A.
Continuous current is in the range of 80 A to 100 A or even also
higher depending on the application.
[0006] For such extreme conditions the connection of the
electrochemical cells of energy storage assembly is extremely
stressed.
[0007] Normally, the connections are provided through crimps,
screws or weld points. Often, the electrochemical cells are damaged
during setting up the connection through thermal and mechanical
stress.
[0008] Accordingly, an object of the invention is to provide an
energy storage assembly whose connections shall exhibit a high
reliability, e.g. up to 15 years, under extreme conditions, e.g. in
a vehicle under high vibration and high temperature. Furthermore
the energy storage assembly shall exhibit a good ampacity (i.e. a
good current carrying capacity, whereas the connection resistance
should be smaller than the internal cell resistance) and high
capacity against thermal and mechanical stress.
SUMMARY OF THE INVENTION
[0009] In order to satisfy this object, an energy storage assembly
is provided with fail-safe connections of the electrochemical cells
through so called poka-yoke (=a fail-safe contact in such a way
that contact elements are designed that they do not misconnect with
each other).
[0010] In accordance with an aspect of the invention, the energy
storage assembly comprises a plurality of flat electrochemical
cells, each of them comprises a pair of electrodes which
electrically connect the electrochemical cells with each other
through outward electrode terminals, wherein each electrochemical
cell comprises as a pair of outward electrode terminals a straight
outward terminal and a curved outward terminal and wherein the
electrochemical cells are connected with each other that a straight
outward terminal of one of the electrochemical cell is connected
with a curved outward terminal of an adjacent electrochemical
cell.
[0011] Such design of the outward terminals allows that the
electrochemical cells do not misconnect. Furthermore, this design
allows an effective, space-saving arrangement of the
electrochemical cells in a pack, e.g. in a battery or energy
storage pack, in which the flat electrochemical cells are stacked
on top of each other. Such a stack arrangement allows a simple and
effective division of the stack into modules of a number of
cells.
[0012] For a fixed, permanent, reliable connection with a high
ampacity each outward terminal comprises at least one bulge.
Preferably, each outward terminal comprises at least two bulges,
which are horizontally separated by a vertical slot (cavity) in the
outward terminal. In a possible embodiment, each outward terminal
is outwardly slotted in two tags. Preferably, one bulge is arranged
on each tag of an outward terminal. Such double arrangement of two
bulges on one outward terminal, especially on each tag of an
outwardly slotted outward terminal allows a simple redundant
connection of the outward terminals of two electrochemical cells
which connect with each other. The slot in each outward terminal
and the bulge on each tag allow an effective current concentration
during resistance welding, whereby the welding is performed
efficiently and with preferably low thermal stress for the
electrochemical cell through high concentration of the welding
current on the bulge, e.g. welding bulge, on each tag. Furthermore,
the outward slot separates the at least two welding connections so
that mechanical stresses in one of the connections have no
influence on the other connection.
[0013] Alternatively, the outward terminals are not slotted and do
not comprise bulges if the outward terminals are connected by
ultrasonic welding.
[0014] In a further embodiment of the invention, the outward
terminals of each electrochemical cell are arranged on opposite
ends of one cell side of their electrochemical cell. Such an
arrangement of the outward terminals on one cell side, e.g. on the
upper side of the cell, and on opposite ends of this side allows a
simple and effective external connection of the outward terminals
with additional bus bars and an effective and space-saving and also
a very good symmetric structure of the battery pack with a simple
connection of the outward terminals. Furthermore, the slotted
outward terminal allows a simple connection of external connected
elements, such as crimp elements and clip elements of cables, etc.,
e.g. by a lithium-ion battery application for cell balancing. In an
alternative embodiment of the invention, the outward terminals of
each electrochemical cell are arranged on one end of one cell side
of their electrochemical cell.
[0015] In accordance with a further aspect of the invention, each
outward terminal has a thickness of at least 1 mm. The thickness
can vary based on particular applications, e.g. of the size of the
energy storage assembly, especially of the size of the single
electrochemical cell. The larger the assembly or cell is the larger
is the thickness of the outward terminal. For example, the
thickness should be in the range of about 1 mm to about 3 mm. This
allows that an additional active electrode surface is given by the
same cell outer surface because the required terminal section is
provided by the new terminal thickness. Furthermore, such terminal
thickness allows a reduction of the transition surface between
inner cell and outer cell, whereby the tightness in this transition
surface is increased.
[0016] In a possible embodiment of the invention, each outward
terminal is composed of at least copper. In a further possible
embodiment, each outward terminal is composed of at least copper
coated with a protection layer. The protection layer is composed of
e.g. stannous or nickel or an alloy, e.g. an alloy of aluminum
manganese or aluminum copper.
[0017] Additionally, the outward terminals can be covered by
fastening elements, such as clip elements, especially plastic clip
elements. Such clip elements arrangement on each terminal allows a
simple protection against corrosion and isolation. In a possible
embodiment the clip element is an L-profile.
[0018] Furthermore, the outward terminals of each electrochemical
cell are connected with the inner part of their electrochemical
cell through coupling elements. Preferably, the coupling elements
are rivets, crimps, screws or in the inner part integrated weld
points, which are welded, e.g. through ultrasonic welding.
[0019] In a further embodiment of the invention, a predetermined
number of electrochemical cells are arranged in at least two or
modules or groups. Preferably, two modules or groups of a number of
cells are separated by a protection element, especially by a fuse
element, e.g. a short-circuit fuse.
[0020] Depending on the application the electrochemical cells are
connected in series, parallel or in parallel-series.
[0021] The invention can be used in electric cars, in hybrid
electric vehicles, especially in parallel hybrid electric vehicles,
serial hybrid electric vehicles or parallel/serial hybrid electric
vehicles.
[0022] The present invention is now further described with
particular reference to the following embodiments in the drawing.
However, it should be understood that these embodiments are only
examples of the many advantageous uses of the innovative teachings
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 shows a view of an energy storage assembly with a
plurality of electrochemical cells which are connected with each
other through pairs of outward terminals of each cell,
[0024] FIG. 2 shows a view of one of the electrochemical cell,
[0025] FIG. 3 shows a view of an electrochemical cell which is
adjacent to the electrochemical cell according to FIG. 2,
[0026] FIG. 4 shows a view of an energy storage assembly with a
plurality of electrochemical cells which are grouped into two or
more modules without a cell-block or cell-module rotation, and
[0027] FIG. 5, 6 each of them show a view of another energy storage
assembly with a plurality of electrochemical cells which are
grouped into two or more modules with a cell-block or cell-module
rotation.
DETAILED DESCRIPTION OF THE DRAWINGS
[0028] The present invention relates to an energy storage assembly.
The present invention can be used in different application, e.g. in
a hybrid electric vehicle, whereby the hybrid electric vehicle
having a driving motor and an internal combustion engine, wherein
the driving motor is driven by power supplied from the energy
storage assembly. Alternatively, the energy storage assembly can
also be used in an electric car having a driving motor driven by
power supplied from the energy storage assembly. Furthermore the
present invention can be used for storing energy, e.g. wind or
solar energy, for which the energy storage assembly is integrated
in a wind or solar energy plant. The invention can be also used for
load leveling applications.
[0029] FIG. 1 shows a view of an energy storage assembly 1 with a
plurality of flat electrochemical cells 2. The assembly 1 is often
called battery pack. Each electrochemical 2 is also called battery
cell or single galvanic cell or prismatic cell.
[0030] Each of the electrochemical cells 2 comprises a pair of
electrodes A and K, whereby one of the electrodes A is an anode or
negative electrode and the other electrode K is a cathode or
positive electrode.
[0031] To electrically connect the electrochemical cells 2 with
each other the electrodes A and K of each cell 2 are connected with
outward terminals 3.A and 3.K. Depending on the application the
electrochemical cells 2 can be connected through the outward
terminals 3.A and 3.K in parallel, in series or in
parallel-series.
[0032] The shown embodiment according to FIG. 1 presents
electrochemical cells 2 which are connected in series.
[0033] For fail-safe installation and assembling, especially a
fail-safe connection of the electrochemical cells 2 with each
other, the pair of outward terminals 3.A and 3.K of each cells 2
are differently designed in that one of the outward terminals, e.g.
the outward anode terminal 3.A, has a straight form; the other
outward terminal of the same cell 2, e.g. the outward cathode
terminal 3.K, has a curved form or vice versa. Furthermore, the
outward terminals 3.A and 3.K of adjacent electrochemical cells 2,
which are connected with each other, are also differently designed
in that one of the connected outward terminals, e.g. the outward
anode terminal 3.A, of one of the electrochemical cells 2 has a
straight form; if these cells 2 are parallel connected with each
other the outward anode terminal 3.A of the adjacent
electrochemical cell 2 has a curved form; if these cells 2 are
connected in series with each other the outward cathode terminal
3.K of the adjacent electrochemical cell 2 has a curved form.
[0034] With other words: For a space-saving and fail-safe
installation and assembling of the whole energy storage assembly 1
the electrochemical cells 2 are connected with each other that a
straight outward terminal 3.A or 3.K of one of the electrochemical
cells 2 is connected with a curved outward terminal 3.A or 3.K of
an adjacent electrochemical cell 2 depending on the kind of
connection, e.g. in parallel, in series or in parallel-series.
[0035] Each electrochemical cell 2 is a flat cell, which comprises
e.g. as electrodes A and K a plurality of not shown inner electrode
film, whereby different electrode films separated by a not shown
separator film rinsed with an e.g. non-aqueous electrolyte.
Alternatively, plates can be used instead of films. Depending on
the kind of cell 2, e.g. a lithium-ion cell; the electrode films
are divided in two different groups of films. One group of the
electrode films represents the cathode or positive electrode K,
e.g. of a lithium-transition metal oxide, the other group of the
electrode films represents the anode or negative electrode A, e.g.
of metallic lithium or lithium graphite.
[0036] More specifically, the outward terminals 3.A, 3.K of each
electrochemical cell 2 are connected with the inner part of their
electrochemical cell 2, especially with the respective electrodes
A, K through not shown coupling elements. The coupling elements can
be provided as rivets, crimps, bolts or weld points.
[0037] Furthermore, the arrangement of electrode films with
separator films is surrounded by a casing 4. The casing 4 can be
provided as a film casing or a plate casing which isolates the
cells 2 of each other. Preferably, the cells 2 are at least
electrically isolated of each other. Additionally, the cells 2 can
be thermally isolated of each other depending on the used material.
Alternatively, the cells 2 can be electrically connected through
the casing surface. Another alternative embodiment can be provided
in that a material, e.g. a resin, is filled between the cells 2 for
electrical isolation.
[0038] Depending on the kind and size of the energy storage
assembly 1 the outward terminals 3.A, 3.K of each electrochemical
cell 2 are arranged on opposite ends of one cell side 2.1 of their
electrochemical cell 2. Alternatively, the outward terminals 3.A,
3.K of each electrochemical cell 2 can be arranged on one end of
the cell side 2.1 (not shown).
[0039] For a simple installation of the energy storage assembly 1
with the plurality of cells 2 (also called battery pack or package)
the cells 2 are fixed on a bottom plate 5 by form or friction
fitting of each cell 2 in the plate 5.
[0040] The whole energy storage assembly 1 can also be surrounded
by a not shown casing.
[0041] Regarding FIGS. 2 and 3 each of them shows a single
electrochemical cell 2, which are adjacent in the energy storage
assembly 1 according to FIG. 1 and which are to be connected with
each other in series.
[0042] For a strong connection of the relevant outward terminals
3.A and 3.A, 3.K and 3.K to be connected, one of the outward
terminals 3.K or each outward terminal 3.A and 3.K comprises at
least one bulge 6. In the described embodiment according to FIGS. 2
and 3 each outward terminal 3.K of the cells 2 comprises two bulges
6.
[0043] To reduce mechanical stresses during welding of the outward
terminals 3.A and 3.K, 3.K and 3.A to be connected, each outward
terminal 3.A and 3.K is horizontally separated by a vertical slot 7
or cavity, so that each outward terminal 3.A, 3.K is outwardly
slotted in two tags 3.A.1 and 3.A.2 or 3.K.1 and 3.K.2. Such slot 7
allows that two bulges 6, wherein one bulge 6 is arranged on each
tag 3.A.1, 3.A.2, 3.K.1, 3.K.2 of one outward terminal 3.A, 3.K,
are provided for a redundant connection of outward terminals 3.A,
3.K of adjacent cells 2. Furthermore, the outward slot 7 allows at
least two welding connections with reduced mechanical stresses.
[0044] An additional advantage of the slot 7 is that a slotted
outward terminal 3.A, 3.K allows to directly connect e.g. balancing
cables, electric components and other devices to the terminal 3.A,
3.K, especially to the tags 3.A.1, 3.A.2, 3.K.1, 3.K.2.
[0045] Alternatively, sensor elements, such as temperature sensor
elements, can be directly integrated in the outward terminal 3.A,
3.K. This allows a very efficient temperature measurement.
[0046] Especially, depending on the size of the energy storage
assembly 1 the thickness of each outward terminal 3.A, 3.K can be
varied in a range of 1 mm to 3 mm. In one embodiment, each outward
terminal 3.A, 3.K can have a thickness of at least 1 mm.
Alternatively, the outward terminals 3.A, 3.K can have a different
thickness in the above mentioned range depending on the available
space and required compactness and tightness.
[0047] Furthermore, the outward terminals 3.A, 3.K can be formed
differently in that the current distribution from the respective
cell 2 is efficiently performed. For instance, the connecting end
of each outward terminal 3.A, 3.K can have a cone form. The
connecting end of each outward terminal 3.A, 3.K is the end through
which the terminal 3.A, 3.K is connected with the respective inner
electrode A, K.
[0048] Preferably, each outward terminal 3.A, 3.K is composed of at
least copper. Each outward terminal 3.A, 3.K are composed of the
same material. This allows the same welding temperature.
Furthermore, each outward terminal 3.A, 3.K can be composed of at
least copper coated with a protection layer. Preferably, the
protection layer is composed of stannous or nickel against
corrosion. The protection layer is very thin. For instance, the
protection layer has a thickness of a few .mu.m.
[0049] Furthermore, FIGS. 4 to 6 show further embodiments with
grouped electrochemical cells 2.
[0050] FIG. 4 shows the assembly 1 (also called battery pack)
without a cell-block or cell-module M1 to M2 rotation. These result
in crossing of bus bars and big total length of bus bars.
[0051] FIGS. 5 and 6 show the assembly with a cell-block or
cell-module rotation of 180.degree.. These result in mo crossing of
bus bars. The total length reduction of bus bars.
[0052] Preferably, a predetermined number of electrochemical cells
2, e. g. 6 cells or 12 cells are arranged in at least two or more
modules M1 to Mn or groups. For a simple short-circuit fuse of the
cells 2, the modules M1 to M2 are separated by a protection element
P, e.g a fuse, especially a short-circuit fuse.
[0053] Additionally, the outward terminals 3.A, 3.K can be covered
by fastening elements, e.g. clip elements L, especially plastic
clips or plastic L-profiles for protection and isolation.
* * * * *